Public defender clerking --- good experience?

Honestly I kind of think I should do this for (1) the experience [might be really hands-on, substanative?] and (2) the very least that I might do while in school is seek out some of the under-appreciated(?) stuff and take it seriously in deciding what to do with my career.

I said no...I'm a first semester 1L so I don't know anything, but I'll tell you what I think anyway.

I'm guessing if you don't want to do PI work, then you probably don't want to do criminal work. If that's the case then I would recommend you spend your summer doing civil work. Work at a firm or get an internship with a judge or government agency. At the very least you could volunteer at a (civil) legal aid organization. PD seems like such a waste if you don't want to do PI or criminal stuff. I mean, sure you might get hands-on experience, but will it be hands-on experience that you can leverage later on when you look for whatever work you really want to do?

Just so you know where I'm coming from, I plan on being a PD when I graduate and I hope to spend time at a PD's office next summer. It's just that criminal and civil law seem to me to be totally different worlds with limited cross-over potential.

It's good experience, especially as a 2L. It may be worth checking the rules in the state you're looking to extern in; in a lot of states, 2L's can work as essentially junior prosecutors and try their own docket. PD externs can't do so due to the fiduciary relationship between the PD's and their clients, but since a DA's only "client" is the state, they can run the show.

Either way, you get a lot more hands-on experience, just because they're so under staffed. I wouldn't worry so much about the civil/criminal gap at this point (assuming you're a 1L) since you won't be picking up anything invaluable either way. Also look into clerking for a state trial court judge, then you get the criminal and civil sides of things, plus tons of experience.